Re: Exception when caching a SelectQuery with prefetching [WAS: Caching]

[Andrus Adamchik]

Yeah, wouldn't hurt to have a record of this case. Maybe we'll come up  
with some solution, or at least do a bit more testing.

Andrus
On May 20, 2010, at 3:22 PM, Gary Jarrel wrote:

Yes this was in fact the case, works fine with in memory caching.

Should I still lodge a ticket?

G

On Thu, May 20, 2010 at 6:14 PM, Andrus Adamchik <and...@objectstyle.org 
> wrote:
One thing to keep in mind here is that OSQueryCacheFactory is not  
tested
with persistent cache... It works perfect with in-memory cache, but  
I always
thought that persisting the data that is sort of already persisted  
in the DB
doesn't buy us much, so that scenario never got any attention. E.g. I
wouldn't be surprised if de-serialization of the cache causes even  
more
issues.

Andrus


On May 20, 2010, at 10:03 AM, Andrey Razumovsky wrote:

Looks like a bug. Could you please open a ticket?

2010/5/20 Gary Jarrel <garyjar...@gmail.com>

Hi,
I managed to get the cache issue described below resolved, my error
with the DataContextFilter that I was using and it was  
overwriting the
modeler configuration when initializing shared config.

I've ran into another issue with the following code:

SelectQuery q = proto.queryWithParameters(params);
q.addPrefetch(RichProduct.MANUFACTURER_PROPERTY);
q.addPrefetch(RichProduct.RAW_PRODUCT_PROPERTY);
q.setCacheStrategy(QueryCacheStrategy.SHARED_CACHE);
q.setCacheGroups("products");

Upon execution of this query I get the following exception:

ERROR  
com.opensymphony.oscache.base.algorithm.AbstractConcurrentReadCache
[oscache] Exception persisting RichProduct/subCategory =
<ObjectId:SubCategory, category_id=1,
id=1>/categoryName/subCategoryName/cost
com 
.opensymphony.oscache.base.persistence.CachePersistenceException:
Unable to write
'/tmp/cache/application/ 
0/0/5/005126BC80FABAA4C582919EDF0B9304.cache'
in the cache. Exception: java.io.NotSerializableException, Message:
org.apache.cayenne.access.ListWithPrefetches
     at

com 
.opensymphony 
.oscache 
.plugins 
.diskpersistence 
.AbstractDiskPersistenceListener 
.store(AbstractDiskPersistenceListener.java:376)
     at

com 
.opensymphony 
.oscache 
.plugins 
.diskpersistence 
.AbstractDiskPersistenceListener 
.store(AbstractDiskPersistenceListener.java:238)

<rest of stack trace removed>

If I however remove the prefetches then the caching works fine.

Looking at the source code for ListWithPrefetches it does not
implement Serializable, could this be the reason for it, or am I
missing something!

Thank you

Gary

On Wed, May 19, 2010 at 6:17 PM, Gary Jarrel <garyjar...@gmail.com>
wrote:

Hi Guys,
I seem to full of questions today!
In the modeler I've got  
org.apache.cayenne.cache.OSQueryCacheFactory for

Query Cache Factory, 5000 objects and using shared cache.

I can see OSCache initializing in the logs and everything  
appears to be

fine.

However when I try to get the cache from the ObjectContext like  
so:
QueryCache cache = ((BaseContext)  
getObjectContext()).getQueryCache();
The cache that is being returned is

the org.apache.cayenne.cache.MapQueryCache

I've traced the calls and can see that the call got  
getQueryCache() goes

to MapQueryCacheFactory despite the fact that the modeler
specifies OSQueryCacheFactory

Am I doing something wrong here?
Thank you
Gary




--
Andrey